1. Field of the Invention
The present invention relates to a locking device used in an apparatus for fusion splicing optical fibers, and more particularly to a locking device which can easily release the optical fibers without breaking after an operation of splicing the optical fibers.
2. Description of the Related Art
A device for fusion splicing two optical fibers is provided with a pair of optical fiber locking devices, and each of the locking devices is fixed to the apparatus so as to freely move in a mutual direction. Each of the locking devices is provided with a cover which can be opened and closed, and is further provided with a fixing means such as a magnet, a clamp or the like for fixing at the closed position. Each of the respective locking devices receives the optical fiber at an open position thereof, and the optical fibers are fixed at the closed position.
Two optical fibers are fixed to the respective locking devices so that axes thereof coincide with each other, and thereafter front ends of the optical fibers are in contact with each other by moving the respective locking devices. The optical fibers are fused by press-contacting a heating means such as a pair of arc electrodes or the like to the contact front ends so as to heat. The structure is made such that the spliced optical fiber can be taken out by canceling the fixing means mentioned above so as to set the cover at the open position.
In the case of axially symmetric optical fibers, the apparatus and method having the structure mentioned above may be employed, however, in the case of non-axially symmetric optical fibers, for example, polarization maintaining optical fibers or the like, a structure of further adjusting an orientation of a rotational direction is required.
A fusion splicing device for the polarization maintaining optical fibers is provided with a mechanism of rotating the locking device in addition to the structure mentioned above. After rotating the locking devices so that the orientations in the rotational direction coincide with each other after fixing the polarization maintaining optical fiber, the fibers are fused to each other.
In the proposed fusion splicing device mentioned above, an attention is required for an operation of taking out the optical fibers. For example, in the case that a magnet is applied to the fixing means for the cover, since it is necessary to open the cover against a magnetic force of the magnet, a force is applied to the optical fiber in a shearing direction, and this may cause its breaking at worst. Accordingly, it is necessary to hold the locking device by one hand and carefully open the cover by another hand. The operation is laborious for an operator and operability is deteriorated.
Further, in the fusion splicing device for the polarization maintaining optical fiber, since the locking device is rotated for the purpose of coinciding the orientations of the optical fibers as mentioned above, the cover is not necessarily directed to an upper side. In some orientations at a time of firstly fixing the optical fibers, there may be a case where one of them is rotated to be upset. In the case mentioned above, it is necessary for the operator to insert the hand to a back side of the upset locking device so as to perform the operation, and operability becomes significantly deteriorated. It can be considered that the cover is opened after rotating the locking device upward, however, since a force in a twisting direction is applied to the optical fiber in that case, there is a risk of breaking.
The present invention is carried out in light of the problems mentioned above, and an object of the present invention is to provide a locking device for optical fibers which can easily cancel a fixation without damaging the optical fibers.
According to a first aspect of the present invention, an optical fiber locking device is provided with a holder base, a table for support of an optical fiber, the table being fitted to the holder base and provided with a magnet and a slit, an openable and closable cover, being connected to the table by a hinge and magnetically attached by the magnet and a sliding arm including a finger protruding out from the slit so as to operate the cover and a grip, and movably fitted to the holder base. When the grip is driven to a direction of the cover so as to drive the finger, the finger pushes the magnetically attached cover up so as to be opened.
Since the optical fiber is gripped by the table and the cover which are magnetically attached to each other so as to be fixed, it is possible to securely execute a fusion splicing between a pair of optical fibers. After the splicing is finished, it is easy to take out the optical fibers only by moving the grip so as to open the cover.
The optical fiber locking device is more preferably structured such that the sliding arm is provided with a restriction projection which is slidably engaged with the table.
Since the restriction projection is slidably engaged with the table, the cover is not pushed up to the upper side accompanying with a motion that the cover is opened. Accordingly, no force in a shearing direction is applied to the optical fiber, and it is possible to prevent the optical fiber from being damaged.
According to a second aspect of the present invention, the holder base is further provided with a spring which applies a force to the sliding arm in a direction of moving apart from the cover, and the cover is further provided with a recess for being engaged with the finger in addition to the optical fiber locking device having the same structure mentioned above. The finger is engaged with the recess so as to keep a state in which the cover is slightly open.
The cover can be kept in the state of being slightly open only by operating the grip, therefore it is possible to rotate the optical fiber locking device without rotating the optical fiber. Accordingly, even by rotating the optical fiber locking device so as to execute the fusion splicing operation, it is possible to easily open the cover, and a force in a twisting direction is not applied to the optical fiber.
According to a third aspect of the present invention, the optical fiber locking device is provided with a table for supporting an optical fiber, the table provided with a magnet and a slit, an openable and closable cover connected to the table by a hinge and detachably attached by the magnet, and a sliding arm provided with a finger protruding out from the slit so as to operate the cover and a grip, and the sliding arm slidably fixed to the table. When the grip is driven to a direction of the cover so as to drive the finger, the finger pushes the magnetically attached cover up so as to be opened.
According to the third aspect of the present invention, in addition to the same effects as those of the optical fiber locking device according to the first aspect, it is possible to structure the optical fiber locking device in compact since the holder base is not required.